Rebuild/Repowering

[morgan25]

Just bought my 1988 osprey 170 stripper, came with a 1988 merc. 115HP. Don't think the motor is worth saving. From what I'm reading here, seems like I might be better off going down to 90HP with less weight. Otherwise the boat just needs some painting and touch up. Will post photo's soon. Anything other suggestions out there on this boat? Looking for owners manual etc.

[Marcq]

Hey welcome, a lot of new folks with 170 lately, now we need some pictures :)
What's wrong with your 115hp Merc ?

Marc..

[morgan25]

I don't think the 115 merc. has been run in several years, as the registration was dated 06. Anyway, first attempt with fully charged batteries , the motor only turns a 1 inch or 2. I just rebuilt the trailer hubs, so I will get it to the mechanics and let him verify what is going on. From what I have read, it seems 90HP at 261-300 lbs. is tops you want to put on these boats because of the weight. Any thoughts on that theory? The boat seems to be in good shape, no soft spots or major cracks. I am going to pull the gas tank based on it's age, and see what it looks like. When in doubt, replace it. I usually go deep in the back country so I'm leaning towards a yamaha 90 2 stroke as they have them on sale for $5,200.00 right now. Depends what the mech. says.

[Marcq]

the motor only turns a 1 inch or 2.

Could be the starter or bad connections, did you try it without the sparkplug in and turning it by hand ?

From what I have read, it seems 90HP at 261-300 lbs. is tops you want to put on these boats because of the weight. Any thoughts on that theory? .

90hp is plenty of power for the size of the boat. I think on mine I will go for a Merc efi 60hp 4 stroke, don't need to go fast, now it as a 85hp 2s Johnson that weights 301lb, could reduce that to 248lb with the 60 4s and better fuel economy, I use my boat mostly on lakes site seeing and trolling



Marc..

[RickK]

Just bought my 1988 osprey 170 stripper, came with a 1988 merc. 115HP. Don't think the motor is worth saving. From what I'm reading here, seems like I might be better off going down to 90HP with less weight. Otherwise the boat just needs some painting and touch up. Will post photo's soon. Anything other suggestions out there on this boat? Looking for owners manual etc.

Welcome aboard morgan25  :!:  :!:
Our 170 family keeps growing and growing  8)
I agree that you should pull the plugs and try cranking the motor.  Should turn over freely, maybe not at first though.
The motor that was on my 170 when I bought it was a straight-6 merc 150, so the decals said. After investigating I think it was a reworked 115 or so - the boat flew with that motor on it and it took 2 batteries to crank it up when it was cold, starting with barely turning over and then finally firing up.  Once warmed it would fire right up.
Most 90 and 115 are the same weight if by the same mfg, they recarb to get the added HP. A 90hp should be plenty - you should be able to get mid-30s out of her with that motor.

[morgan25]

I puilled the plugs and got her to turn over, I'll put a few drops of oil down her and see what happens. She's going to the mechanic's Wednesday so we will see what happens. Original owner says she ran sweet last time he ran her when lower unit went out.

[John Jones]

When a motor has set up for quite a while and will not turn freely, STOP, remove the plugs and put several squirts of oil or even PB Blaster in each cylinder.  It will prevent scarring the cylinders.